<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>

    <style>
        @keyframes kf_mc {
            /* from: 0% */
            /* to: 100% */
            /* form { */
            0% {
                color: red;
                background-color: orange;
                font-size: 16px;
                width: 200px;
                height: 168px;
            }
            20% {
                color: green;
                background-color: violet;
                font-size: 18px;
                width: 200px;
                height: 168px;
            }
            50% {}
            80% {}
            /* to { */
            100% {
                color: orange;
                background-color: red;
                font-size: 24px;
                width: 168px;
                height: 200px;
            }
        }
        
        .mc {
            /* 
            animation-name: kf_mc;
            animation-duration: 4s;
            animation-delay: 1s;
            animation-timing-function: cubic-bezier(0.895, 0.03, 0.685, 0.22);
            animation-direction: reverse;
            animation-iteration-count: infinite;
            animation-play-state: paused;
            animation-fill-mode: backwards;
             */
            /* animation: name duration timing-function delay iteration-count direction fill-mode; */
            animation: kf_mc 4s ease 1s 2 normal forwards;
        }
        
        @keyframes kf_mc2 {
            /* from: 0% */
            /* to: 100% */
            /* form { */
            0% {
                color: red;
                background-color: orange;
                font-size: 16px;
                width: 200px;
                height: 168px;
                transform: translate(0px, 300px) rotate(0deg);
            }
            20% {
                color: green;
                background-color: violet;
                font-size: 18px;
                width: 200px;
                height: 168px;
            }
            50% {}
            80% {}
            /* to { */
            100% {
                color: orange;
                background-color: red;
                font-size: 24px;
                width: 168px;
                height: 200px;
                transform: translate(0px, 0px) rotate(1080deg);
            }
        }
        
        .mc2 {
            /* 
            animation-name: kf_mc2;
            animation-duration: 4s;
            animation-delay: 1s;
            animation-timing-function: cubic-bezier(0.895, 0.03, 0.685, 0.22);
            animation-direction: reverse;
            animation-iteration-count: infinite;
            animation-play-state: paused;
            animation-fill-mode: backwards;
             */
            /* animation: name duration timing-function delay iteration-count direction fill-mode; */
            animation: kf_mc2 4s ease 1s 2 normal forwards;
        }
    </style>
</head>

<body>
    <div class="mc">HelloWorld</div>
    <div class="mc2">一个筋斗云，十万八千里。</div>
</body>

</html>